The Morrígan ("terror" or "phantom queen") or Mórrígan ("great queen") (also known as Morrígu, Morríghan, Mor-Ríoghain, sometimes given in the plural as Morrígna) is a figure from Irish mythology who appears to have once been a goddess, although she is not explicitly referred to as such in the texts.

She is associated with sovereignty, prophecy, war, and death on the battlefield. She sometimes appears in the form of a crow, flying above the warriors, and in the Ulster cycle she also takes the form of an eel, a wolf, and a cow. She is generally considered a war deity comparable with the Germanic Valkyries, although her association with cattle also suggests a role connected with fertility, wealth, and the land.

She is often depicted as a triple goddess, although membership of the triad varies; the most common combination is the Badb, Macha and Nemain, but other accounts name Fea, Anann, and others.